The invention relates to a system and method of determining preciously the heating value of liquid jet a fuel and the amount of flight time which will be provided by an amount of that fuel. More particularly, the invention provides a system and a method of determining the amount of the net heating value and of flight time (at conditions of flight) which will be provided by an amount of liquid jet fuel to within .+-.0.4%. The prior art does not provide a method or system which determines the net heating value and flight time provided by an amount of fuel to within .+-.0.4%.
Dougherty, et al., in U.S. Pat. No. 4,258,422, discloses the use of fuel density sensors in a liquid gauging system. A system read out is provided for fuel quantity in weight, such as pounds, using a measurement of fuel density. The fuel density may be used with fuel volume to compute fuel weight. In order to determine fuel density, the dielectric constant of the fuel may be measured by a fuel density sensor. In conjunction with the analogue circuitry within the primary indicator, a system microcomputer may then compute a fuel density value using a relationship between dielectric constant and density. One density sensor is installed in each fuel tank such that the density sensor is completely covered by fuel when the system is in operation. I. H. Cohn, et al., in U.S. Pat. No. 3,523,186, discloses an attitude error correction fluid gauging system employing radiation detectors and error storage techniques. An indicated volume signal is derived from the radiation detectors and a densitometer. Rosie, et al., in U.S. Pat. No. 4,229,798, discloses a liquid storage tank contents gauge which measures temperature by a sensor, such as a thermoster, a thermocouple or a resistance thermometer and the electrical signal produced controls a voltage controlled oscillator. Weitz, Jr., et al., in U.S. Pat. No. 4,011,746, discloses a liquid density measurement system which includes a temperature sensor and a capacitance probe. Stansfeld, U.S. Pat. No. 4,007,627, discloses a density transistor. Messer, U.S. Pat. No. 3,222,927, discloses a continuous process for determining moisture content and heat of combustion of solid fuels. Hartford, et al., U.S. Pat. No. 4,252,097, discloses a viscosity compensated fuel injection system. Swoboda, U.S. Pat. No. 4,442,700, discloses an ultrasonic hydrometer. Stansfeld, in U.S. Pat. Nos. 4,262,532 and 3,916,672, discloses the measurement of fluid density and specific gravity.